diff --git a/core/modules/system/src/Tests/System/HtaccessTest.php b/core/modules/system/src/Tests/System/HtaccessTest.php
index 3e8f36d..00e8ea7 100644
--- a/core/modules/system/src/Tests/System/HtaccessTest.php
+++ b/core/modules/system/src/Tests/System/HtaccessTest.php
@@ -15,21 +15,51 @@
  * @group system
  */
 class HtaccessTest extends WebTestBase {
+  /**
+   * Get an array of file paths for access testing.
+   *
+   * @return array
+   *   An array of file paths to be access-tested.
+   */
+  protected function getProtectedFiles() {
+    $path = drupal_get_path('module', 'system') . '/tests/fixtures/HtaccessTest';
+    $file_exts = [
+      'engine',
+      'inc',
+      'install',
+      'make',
+      'module',
+      'profile',
+      'po',
+      'sh',
+      'sql',
+      'theme',
+      'twig',
+      'tpl.php',
+      'xtmpl',
+      'yml',
+    ];
+
+    foreach ($file_exts as $file_ext) {
+      $file_paths[] = "$path/access_test.$file_ext";
+    }
+
+    return $file_paths;
+  }
 
   /**
-   * Tests accessing files with .yml extensions at various locations.
+   * Iterates over protected files and calls assertNoFileAccess().
    */
-  public function testYamlFileAccess() {
-    // Try accessing the core services YAML file.
-    $this->assertNoFileAccess('core/core.services.yml');
-    // Try accessing a core module YAML file.
-    $this->assertNoFileAccess('core/modules/system/system.services.yml');
+  public function testFileAccess() {
+    foreach ($this->getProtectedFiles() as $file) {
+      $this->assertNoFileAccess($file);
+    }
   }
 
   /**
    * Asserts that a file exists but not accessible via HTTP.
    *
-   * @param $path
+   * @param string $path
    *   Path to file. Without leading slash.
    */
   protected function assertNoFileAccess($path) {
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.engine b/core/modules/system/tests/fixtures/HtaccessTest/access_test.engine
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.inc b/core/modules/system/tests/fixtures/HtaccessTest/access_test.inc
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.install b/core/modules/system/tests/fixtures/HtaccessTest/access_test.install
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.make b/core/modules/system/tests/fixtures/HtaccessTest/access_test.make
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.module b/core/modules/system/tests/fixtures/HtaccessTest/access_test.module
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.po b/core/modules/system/tests/fixtures/HtaccessTest/access_test.po
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.profile b/core/modules/system/tests/fixtures/HtaccessTest/access_test.profile
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.sh b/core/modules/system/tests/fixtures/HtaccessTest/access_test.sh
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.sql b/core/modules/system/tests/fixtures/HtaccessTest/access_test.sql
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.theme b/core/modules/system/tests/fixtures/HtaccessTest/access_test.theme
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.tpl.php b/core/modules/system/tests/fixtures/HtaccessTest/access_test.tpl.php
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.twig b/core/modules/system/tests/fixtures/HtaccessTest/access_test.twig
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.xtmpl b/core/modules/system/tests/fixtures/HtaccessTest/access_test.xtmpl
new file mode 100644
index 0000000..e69de29
diff --git a/core/modules/system/tests/fixtures/HtaccessTest/access_test.yml b/core/modules/system/tests/fixtures/HtaccessTest/access_test.yml
new file mode 100644
index 0000000..e69de29